Often when women become stepmothers, they believe they should behave like Julie Andrews in the movie "The Sound of Music." They expect instantly to be perfect caregivers and homemakers. Many assume that if they cook and care for stepkids daily, maybe even doing special things such as handcrafting clothing for the children, they'll soon be happily riding bikes with their stepchildren, singing and acting like one big happy family.

These high expectations, which reflect society's view of women as natural caretakers, lead many stepmoms to try to do too much, say experts. Yet if a stepmother assumes a traditional parenting role with her stepchildren and tries to impose new rules, her good intentions may backfire. The kids may reject her attempts to create a nice home for them, her husband's ex-wife may resent her, and her new husband may feel caught between her and the children. In addition, she will probably feel unappreciated and resentful.

According to many stepchildren and experts, the most successful stepmoms don't try to replace or act as though they're the child's real mother, They understand that their role should be that of adult friends or mother figures who leave parenting responsibilities - such as most discipline - to the parents.

It's also important to embrace a go-slow approach, advises James Bray, co-author of the book "Stepfamilies: Love, Marriage and Parenting in the First Decade."

Another approach is for stepmothers to take a hard look at their expectations, learn about common stepfamily challenges, and, with the help of their new spouses, define their roles, suggests Margorie Engel, president of the Stepfamily Association of America in Lincoln, Neb. They need to understand they can't instantly create a whole new family, she adds, but should honor the relationships that existed before they became stepmoms.

"If stepmoms understand their roles, they are in much better shape," she says. "A stepparent is an additional parental figure, not a replacement, even if the parent has died. A stepparent's responsibility is to be an important support system to the spouse."

Stepmoms will spark less resentment in children if they encourage their husbands to continue serving as their children's primary caregivers, says Ms. Engel. If the dad hands over all the parenting responsibility to his new wife, his children may worry that they're going to lose their connection with their father.

Bray puts it more directly: "Stepparents need to focus on forming a relationship with their stepkids and letting the parent take on the parenting role. Otherwise, kids resent it."

However, it isn't always easy for a stepmom to accept and nurture her husband's connection with his kids, says Suzen Ziegahn, a stepfamily consultant in Wisconsin Rapids, Wis., and author of the book "Seven Steps to Bonding With Your Stepchild."

"Stepparents in general - men as well as women - are threatened by the time, privacy, and closeness that a biological parent and his or her kids want," Dr. Ziegahn says. "They want to feel like part of the family."

But if a stepmom can give her husband and stepchildren the space and time to be together, her efforts will pay off in the long run, she adds.

Ryan Tracy, an adult stepchild in Denver, describes his stepmother, Patti Tracy, as his "hero," in part because she supported his tight bond with his father.

"There were a lot of women who would have felt threatened by me because my father loved me fiercely and unconditionally," says Mr. Tracy. "But my stepmom accepted that right from the start. There was never any jealousy. She is an amazing person. She is my role model, and the person I measure all people against."

Encourage mother-child closeness

Some stepmothers have also discovered that, difficult though it may be, they need to also accept and honor their stepchildren's tight bond with their biological mothers.

That was Jann Blackstone-Ford's experience. After she remarried, she agreed to care for her two stepchildren - along with her biological children - on a day-to-day basis while her husband's ex-wife worked full time.

"Initially, I didn't get along with my husband's ex. Not at all. We had every issue you could possibly think of," says Ms. Blackstone-Ford, a divorce mediator in Discovery Bay, Calif. "She was jealous that the kids took to me. I was jealous that they liked her better."

Two of the four children in the household reacted to the tension with nightmares and stomachaches, says Blackstone-Ford. When she, her husband, and his ex-wife realized their relationships were at the root of the trouble, they entered mediation together.

Eventually, Blackstone-Ford became friends with Sharyl Jupe, her husband's ex, and they wrote a book together, "Ex-Etiquette For Parents: Good Behavior After a Divorce or Separation," which was released in October.

While stepmoms can't expect to write books with their husbands' ex-wives, they do need to recognize the strong connection between stepchildren and their biological mothers. Stepmothers shouldn't compete with the kids' mothers for the prize of "best mom," says Engel.

Stepmother Jodie Luksha of West Boylston, Mass., agrees. "The most important thing stepmoms can do for their stepkids is communicate well with their mother," she says.

When Ms. Luksha first became a stepmom, she decided to tell her stepchildren's mother that she supported her role in the family. As a stepchild herself, Luksha understood what it took to be a great stepmother.

"At first, my husband's ex didn't want me in her yard or picking up the kids," she says. But then Luksha took a risk and reached out to her husband's former wife.

"I told her, 'I think your kids are great kids, and you are doing a great job with them.' I said, 'I understand how hard this must be for you. I understand what it's like to be the child of divorced parents. I want your kids to grow up in a healthy environment. The only way to do that is for us to get along.' "

That paved the way to a much better relationship between the two. Now Luksha gets invited to all the children's sporting events, plays, and other school events, including parent-teacher conferences.

While stepmothers are opening up the communication lines, they should learn how the family operated before they entered it, advises Ziegahn. Then, if possible, avoid changing things too quickly, if at all.

A stepmom who feels jealous of her husband's ex-wife will often try to re-make the family's rules and traditions, she says. And that becomes a bone of contention.

Work as a team

What if a stepmom isn't happy with the way her husband or his ex-wife is raising the children? Choose your battles, suggests Ziegahn. "You need your new husband to work with you. You have to say, 'I'm uncomfortable with this, I'd like you to help me change this.' It's got to be a team effort."

Daphne Stevens, a psychologist and stepmom in Macon, Ga., opposed the fact that her husband allowed his teenagers to smoke cigarettes. Ultimately, the couple worked out a compromise: They said the teens could not smoke in the house.

After weathering her initial troubles with being a stepmother, Blackstone-Ford learned the importance of parents and stepparents working as a team. Even though her stepkids spent more time with her than with their biological mother, Blackstone-Ford embraced what experts say is an important guideline in stepfamilies: The biological parents create the rules; the stepparents enforce them.

But it wasn't always easy.

When to speak up and when not to

When her stepson, Steven, was 17, he wanted a tattoo. Blackstone-Ford opposed the idea, but Steven's parents supported his choice. As the stepparent, Blackstone-Ford decided her role in this instance was to "keep [her] mouth shut."

At times, stepmoms have to set limits, especially if they feel the stepkids' behavior could harm their own children, notes Dr. Stevens.

When that happens, the children learn that it's OK for their parents and stepparents to have different parenting styles. "Our kids ended up being blessed by his style and my style," she says.

Like Stevens and Blackstone-Ford, stepmoms who view themselves as a support system for their stepchildren's biological parents are likely to find it easier to connect with their stepchildren, family specialists say. Children will feel more comfortable with stepmoms who aren't trying to usurp their parents' roles.

"The children don't want to forget the past," says Engel.

In fact, stepmoms eager to bond with their stepchildren should begin by learning as much as possible about the children's past, says Ziegahn. They should try to identify the children's interests and find ways to connect with the children on their own terms.